Fluorine (F) and arsenic (As) are inorganic elements present in the subsurface depending on the geology of the region. These compounds are found in high concentrations in the underground strata of Guadiana Valley of Durango affecting water quality for human consumption (NOM-127-SSA-1994). In the present research the main objective was to assess the behavior in time and space of fluoride (F-) and arsenic concentration, from 1996 to date, in the groundwater of the city of Durango and some wells of the rural area as a reference. The highest concentration of arsenic was found in a rural well, Colonia Hidalgo (0.149 mg/L or ppm), 6 times the maximum permissible limit (MPL); within the city well 54 located in the western sector had the highest value (0.076 ppm), 3 times the MPL, 67% of the wells in the city and 60% of the Guadiana Valley had levels that exceeded the MPL (0.025 ppm), the concentration in the city ranged from 0.009 to 0.149 ppm and from 0.08 to 0.15 ppm for the rural zone. With respect to F-, the highest value was also found in the Colonia Hidalgo well (17.8 mg/L), 12 times the MPL; within the city the highest value was recorded in well 16 in the eastern sector with 7.6 ppm (5 times the MPL) 97% of the wells in the city and 100% of the wellsin the Guadiana Valley rural area had concentrations greater than MPL (1.5 ppm), the concentration in the city ranged from 1.1 to 7.6 ppm, while in the Guadiana Valley from 1.7 to 17.8 ppm. Statistical analysis showed no significant difference for fluoride concentration over time (1996-2013); whereas the concentration of arsenic decreased, probably due to the degree of precision required for such small concentrations in groundwater and different analysts ran the samples.